132 MASS. EXPERIMENT STATION BULLETIN 176. 



Earthenware pots 6 inches in diameter and 5 inches deep were used. 

 Each pot was filled with 2 kilos of the air-dried soil. The lime was applied 

 to the surface and thoroughly worked in. The manganese sulfate was 

 applied in solution. The soil was kept at a 25 per cent, moisture content. 

 The clover seed was first soaked for eight hours in a solution of calcium 

 hypochloride, and then seeded on the surface of the soil and pressed into 

 contact with it. The soil was then covered with a half-inch layer of 

 washed quartz and sand to act as a mulch. The treatment employed is 

 shown in the table, there being two pots in each treatment. 



The Series of Pot Cultures. 



The seeds were planted on March 7 and 8, and began to show above 

 the sand on the 9th, and most of them had sprouted by the 15th, when 

 all the pots were watered for the first time. The plants came up rather 

 unevenly, and some replanting was necessary. The replanting was done 

 with seedlings sprouted on paraffine plates. On April 3 all the pots were 

 thinned to 25 plants. The poorest pots at this time were Nos. 3 and 5, 

 the extracted soil with and without the addition of manganese. All of 

 the pots treated with manganese sulfate without lime were poorer than 

 those receiving lime. On April 24 the above differences were even more 

 striking. The plants on No. 5 had practically all died, while on No. 6, 

 where calcium carbonate had been added, they made a small growth. All 

 of the plants on the extracted soil were poorer than those on the other 

 pots. The extraction had probably removed most of the soluble nutri- 

 ents. 



The clover was weighed in both the green and dry states, with the 



